Effect of surface species on Cu-TiO2 photocatalytic activity

• DOI: 10.1016/j.apsusc.2007.09.002
• Publication Date: 2007-09-07T13:21:44Z
• Authors: Baifu Xin; Peng Wang; Dandan Ding; Jia Liu; Zhiyu Ren; Honggang Fu
• Keywords: 7. Clean energy; 01 natural sciences; 0104 chemical sciences

Abstract The Cu-TiO 2 nanoparticles with different Cu dopant content were prepared by sol–gel method. The structure of the as-prepared catalysts and the surface species of Cu-TiO 2 were determined using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and diffuse reflection spectroscopy (DRS). The relationship between the photocatalytic activity and the surface species of Cu-TiO 2 was revealed via the measurement of surface photovoltage spectroscopy (SPS) as well as the degradation of the rhodamine B (RhB). The experimental results suggest that the Cu-TiO 2 photocatalysts with appropriate content of Cu (about 0.06 mol%) possess abundant electronic trap, which effectively inhibits the recombination of photoinduced charge carriers, improving the photocatalytic activity of TiO 2 . While at high Cu dopant region (>0.06 mol%), the excessive oxygen vacancies and Cu species can become the recombination centers of photoinduced electrons and holes. Meanwhile, at heavy Cu doping concentration, excessive P-type Cu 2 O can cover the surface of TiO 2 , which leads to decrease in the photocatalytic activity of photocatalyst. The photocatalytic experimental results are in good agreement with the conclusions of SPS measurements, indicating that there is a close relationship between the photocatalytic activity and the intensity of SPS spectra.